Drop .gitignore, simplify install instructions

Installers extract directly into AddOns and just strip the -master
suffix from the archive folder name.

.gitignore

@@ -1 +0,0 @@
-.claude/settings.local.json

README.md

@@ -7,8 +7,8 @@ The addon is early in development, and most frames have a generic name or aren't
 
 [Download here](https://github.com/Narcasung/hide-coa-ui/archive/refs/heads/master.zip).
 
-Extract the archive, rename the extracted folder to `HideCoAUI`, then drop it
+Extract the archive in your `Interface\AddOns` folder and remove the `-master`
-into your `Interface\AddOns` directory.
+suffix from the extracted folder name.
 
 ## Usage